Advancements in information technology (IT) equipment present challenges in creating a more effective IT environment in data centers and networking facilities. Equipment enclosures designed for high power density applications employing servers and networking equipment typically must provide not only effective cable management and power distribution, but also adequate cooling and ventilation to assure proper and reliable operation of equipment. Equipment rack enclosures for use in such high heat generating applications are primarily configured and equipped to provide front-to-back airflow to accommodate the standard front-to-back airflow pattern used by IT equipment for cooling and ventilation. However, IT equipment racks and enclosures generally cannot provide adequate cooling and ventilation for equipment that typically uses a side-to-side airflow, such as certain types of telecommunications equipment. When an IT equipment enclosure includes equipment using side-to-side airflow and equipment using front-to-back airflow, the air intakes of the side-to-side equipment typically share the enclosure interior with the exhaust vents of all of the equipment. As a result, the air intakes of equipment using side-to-side airflow often do not receive sufficient cooling air required for proper operation of the equipment. Insufficient cooling air can cause overtemperature shutdown and unreliable performance and reduced lifetime of the equipment. IT equipment enclosures and racks configured to provide front-to-back airflow, therefore, are essentially incompatible with airflow patterns of some types of electronic equipment using side-to-side airflow for cooling and ventilating, such as certain types of telecommunications components.
Conventional solutions to this problem include mounting, for example, telecommunications equipment in open-frame racks to promote air circulation through components. Open-frame configurations do not confine hot and warm exhaust air within an enclosure or around equipment air intakes; however, such configurations do not prevent circulation of exhaust air to equipment air intakes and, therefore, do not overcome problems of insufficient cooling and overheating of equipment. Telecommunications equipment disposed in side-by-side rack configurations are susceptible to direct intake of exhaust air vented from adjacent or neighboring equipment and, as a result, have an increased risk of overheating during operation.
Another solution includes incorporating fans in a top of a housing of an enclosure to draw hot and warm air vertically upward from within a rack to vent exhaust air through the enclosure top. Such top-mounted fans, however, do not assure sufficient cooling air will be provided to air intakes of all equipments components mounted in a rack. Nor do top-mounted fans prevent exhaust air from circulating to air intakes of such components. Top-mounted fans can further overdrive airflow through a rack and can cause significant mixing of exhaust air with cooling air. Mixing exhaust air with cooling air can reduce the efficiency of a network room or data center's cooling system. Using top-mounted fans limits the space available on an enclosure top for other functions, including data and power cabling. In addition, top-mounted fans restrict the size and location of equipment that can be mounted in upper sections of the enclosure due to interference with fan airflow.
Further, the overall efficiency, cost, reliability and cooling capacity of a cooling system of a network room or data center is directly related to the ability to separate cooling air from hot and warm exhaust air within an equipment enclosure during operation of equipment. Separation of exhaust air from cooling air is a result of proper installation of rack enclosures; however, present enclosure and rack designs and cooling solutions for electronic equipment using side-by-side airflow do not separate exhaust air from cooling air. In the past, circulation of exhaust air with cooling air was not problematic because the power density of equipment, for instance, telecommunications equipment was significantly less than an average of 1 kW per rack. Current designs of telecommunications equipment, however, may consume 6 kW or more per rack, and, thus, require effective cooling methods.